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1 function retval = triu (x, k) |
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2 |
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3 # usage: triu (x, k) |
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4 # |
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5 # Return the upper triangular part of x above the k-th diagonal. If |
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6 # the second argument is omitted, k = 0 is assumed. |
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7 # |
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8 # See also: tril, diag |
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9 |
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10 if (nargin > 0) |
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11 [nr, nc] = size (x); |
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12 retval = x; |
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13 endif |
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14 |
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15 if (nargin == 1) |
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16 k = 0; |
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17 elseif (nargin == 2) |
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18 max_nr_nc = max (nr, nc); |
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19 if ((k > 0 && k > nc - 1) || (k < 0 && k < 1 - nr)) |
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20 error ("triu: requested diagonal out of range") |
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21 endif |
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22 else |
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23 error ("usage: triu (x [, k])"); |
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24 endif |
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25 |
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26 for j = 1:nc |
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27 for i = j+1-k:nr |
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28 retval (i, j) = 0.0; |
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29 endfor |
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30 endfor |
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31 |
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32 endfunction |
